linuxptp is an implementation of the Precision Time Protocol (PTP) according to IEEE standard 1588 for Linux. The dual design goals are to provide a robust implementation of the standard and to use the most relevant and modern Application Programming Interfaces (API) offered by the Linux kernel. Supporting legacy APIs and other platforms is not a goal.

matrixclock is a clock for Matrix Orbital alphanumeric displays. It's only been tested against the LCD2041 model and in linux, shouldn't be hard porting it to other POSIX environments though. It can show normal, Internet, and binary time.

ntpdate is a simple and small replacement for the
homonymous and obsolete tool from the NTP
Project's (www.ntp.org) reference implementation.
ntpdate sets the local date and time by polling
the Network Time Protocol (NTP) server(s) given as
the server argument to determine the correct time.
It must be run as root on the local host. It is
not meant for real time synchronization.